1. Field of the Invention
The present invention relates to a method for protecting crops from suffering various damages. More particularly, it relates to a method for protecting crops from suffering various damages such as, cold-weather damage or frost damage, fading of green color, damage from photochemical oxidants, wilting of leaves, and the like, which comprises applying polyamine compounds represented by the following general formula (I): EQU H.sub.2 N--R.sub.1 --NH.sub.2 (I)
[wherein R.sub.1 represents a group of--(CH.sub.2).sub.n --(wherein n represents an integer of 4-18),--(CH.sub.2).sub.3 NH(CH.sub.2 (.sub.4 --,--(CH.sub.2).sub.4 --NH(CH.sub.2).sub.4 --,--(CH.sub.2).sub.3 NH(CH.sub.2).sub.3 NH(CH.sub.2).sub.3 --,--(CH.sub.2 (.sub.3 NH(CH.sub.2).sub.4 NH(CH.sub.2).sub.3 --, ##STR1## a fluorenylene group, a naphthylene group, or a group of ##STR2## or an acid addition salt thereof.
2. Description of the Prior Art
Further investigations have led to the discovery that the application of the compounds of the general formula (I) and the acid addition salts thereof to the crops provides various effects such as reduction of cold-weather damage or frost damage to crops, retardation of fading of green color of green crops, reduction of injury to crops from photochemical oxidants, retardation of wilting of leaves of crop plants, etc.
Several methods or chemicals for protecting crops from suffering various damages other than injury from herbicides are known. For example, as the chemicals for reducing cold-weather damage to crops, there are known CCC [(2-chloroethyl)trimethylammonium chloride], B-995 (N-dimethylaminosuccinamic acid), Amo-1618 [(4-hydroxy-5-isopropyl-2-methylphenyl)trimethylammonium chloride, 1-piperidine carboxylate)], etc. [Nobutaka Takahashi et al.; Shokubutsu Choseibusshitsu no Engei-teki Riyo (Horticultural Use of Plant Growth Regulator), p. 225 issued by Seibundo Shinko Sha (Oct. 30, 1973)]. As the method for reducing frost damage, there are known the method of using smoke (Japanese Laid-Open patent application No. 39,245/76), etc. As the chemicals for retarding fading of green crops, there are known kinetin (N.sup.6 -furfurylaminopurine) [Yoshio Masuda, et al.; Shokubutsu Horumon (Plant Hormone), p. 219, issued by Asakura Shoten (Dec. 20, 1971)]etc. As the chemicals for reducing injury to crops from photochemical oxidants, there are known xanthone (Japanese Laid-Open patent application No. 31,030/75), etc. As the chemicals for retarding wilting of leaves of crop plants, there are known kinetin [Yoshio Masuda et al.; Shokubutsu Horumon (Plant Hormone), p. 230, issued by Asakura Shoten (Dec. 20, 1971)], and the like.
However, the compounds of the general formula (I) and the acid addition salts thereof of the present invention are different in structure from any of these compounds.